Examples should be using `sizes` and `srcset`

[yoavweiss]

Awesome grunt task! :) One nit though... Seems like the example on http://www.andismith.com/grunt-responsive-images/ (as well as the copy) is using the full <picture> syntax, where they actually shouldn't.

Since AFAICT this grunt task does not involve art-direction (e.g. no cropping, proportion change, etc), the examples would be significantly better off showing the <img sizes srcset> syntax, which is the best fit for the use-case tackled by this task.

So the example syntax should be: <img sizes="(min-width: 820px) 800px, (min-width: 640px) 640px, 320px" srcset="wedding-small.jpg 320w, wedding-medium.jpg 640w, wedding-large.jpg 800w">